This attack forces an integer variable to go out of range. The integer variable is often used as an offset such as size of memory allocation or similarly. The attacker would typically control the value of such variable and try to get it out of range. For instance the integer in question is incremented past the maximum possible value, it may wrap to become a very small, or negative number, therefore providing a very incorrect value which can lead to unexpected behavior. At worst the attacker can execute arbitrary code.

An integer overflow vulnerability was found in optipng, an advanced PNG optimizer that also recognizes other external file formats. This may lead to arbitrary code execution when a maliciously crafted TIFF file is processed.
For Debian 7 'Wheezy', these problems have been fixed in version 0.6.4-1+deb7u3.
We recommend that you upgrade your optipng packages.
NOTE: Tenable Network Security has extracted the preceding description block directly from the DLA security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote host is affected by the vulnerability described in GLSA-201801-02 (OptiPNG: Multiple vulnerabilities)
Multiple vulnerabilities have been discovered in OptiPNG. Please review the referenced CVE identifiers for details.
Impact :
A remote attacker could entice a user to process a specially crafted image file, possibly resulting in execution of arbitrary code with the privileges of the process or a Denial of Service condition.
Workaround :
There is no known workaround at this time.

Security fix for CVE-2017-1000229 and CVE-2017-16938
Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Security fix for CVE-2017-1000229 and CVE-2017-16938
Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

It was discovered that OptiPNG incorrectly handled memory. A remote attacker could use this issue with a specially crafted image file to cause OptiPNG to crash, resulting in a denial of service, or possibly execute arbitrary code.
Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.